1. Technical Field
This application was filed claiming Paris Convention priority of Japanese Patent Application No. 2008-287062, the entire content of which is herein incorporated by reference.
The present invention relates to a process for producing methionine from 3-methylthiopropanal as a raw material by cyanohydrination, hydantoination, and hydrolysis. Methionine is useful as additives for animal feed.
2. Background Art
As a process for producing methionine, a process in which a raw material, 3-methylthiopropanal is reacted with hydrogen cyanide in the presence of a base (a cyanohydrination step); subsequently, the resulting product is reacted with ammonium carbonate (a hydantoination step); and then the resulting product is hydrolyzed to give methionine is widely known (see JP-A-2002-114758, JP-A-2002-105048, JP-A-2003-104958, JP-A-2003-104959, JP-A-2003-104960, JP-A-10-182593, JP-A-2003-119557, JP-A-11-217370 and JP-A-2007-314507).
In the production process, the step for hydrolysis of hydantoin has a defect in which pipes and reaction vessels are easily corroded, and therefore, pipes and reaction vessels made of a corrosion-inhibiting material are generally used (see JP-A-10-182593, JP-A-2003-119557, JP-A-11-217370 and JP-A-2007-314507).